/****************************************************************
 * Licensed to the Apache Software Foundation (ASF) under one   *
 * or more contributor license agreements.  See the NOTICE file *
 * distributed with this work for additional information        *
 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
 * "License"); you may not use this file except in compliance   *
 * with the License.  You may obtain a copy of the License at   *
 *                                                              *
 *   http://www.apache.org/licenses/LICENSE-2.0                 *
 *                                                              *
 * Unless required by applicable law or agreed to in writing,   *
 * software distributed under the License is distributed on an  *
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
 * KIND, either express or implied.  See the License for the    *
 * specific language governing permissions and limitations      *
 * under the License.                                           *
 ****************************************************************/

package org.apache.james.webadmin;

import java.io.IOException;
import java.net.ServerSocket;

import com.google.common.base.Supplier;
import com.google.common.base.Suppliers;
import com.google.common.base.Throwables;

public class RandomPort implements Port {

    public static int findFreePort() {
        try (ServerSocket socket = new ServerSocket(0)) {
            return socket.getLocalPort();
        } catch (IOException e) {
            throw Throwables.propagate(e);
        }
    }

    private final Supplier<Integer> portSupplier;

    public RandomPort() {
        portSupplier = Suppliers.memoize(RandomPort::findFreePort);
    }

    @Override
    public int toInt() {
        return portSupplier.get();
    }

}
